A vehicle system that includes multiple vehicles coupled together to travel together along a route may be known as a vehicle consist. For example, a vehicle system may include one or more powered vehicles that may be mechanically linked (directly or indirectly) to non-powered vehicles. The powered and non-powered vehicles of the vehicle system may travel as a group along a designated route. In cases where the vehicle system includes multiple powered vehicles, the vehicle system may coordinate operations of the powered vehicles to move the vehicle system. For example, a train may include a locomotive consist that has one or more locomotives mechanically coupled to one or more rail cars. Locomotives in a single consist may include a lead locomotive and one or more remote locomotives. The lead locomotive may control operation of the remote locomotive(s). More specifically, the lead locomotive may coordinate tractive and braking operations of the different locomotives to control movement of the locomotive consist. In some cases, a single train may include a plurality of such locomotive consists. The locomotive consists may communicate with one another to coordinate tractive and braking operations of the train.
Two or more of the vehicles in a vehicle system may each include an on-board controller or other electronics that are connected to a respective on-board vehicle communications network. In certain cases, it may be desirable to link the individual on-board vehicle communications networks, such that electronics of one vehicle can communicate with electronics of other vehicles. However, in certain systems, it may be the case that electronics on different vehicles will have the same network address (e.g., IP address). For example, in certain PTC (positive train control) systems or other train safety systems, standards may be adopted requiring that in each PTC-equipped locomotive, equipment used for PTC communications and control (e.g., PTC radio and PTC controller) have the same network addresses, as a function of category. For example, all PTC radios may have a first common network address, all PTC controllers may have a second common network address, and so on. This enables on-board electronics to communicate with each other within the corresponding vehicle communications network using the same known network addresses. For example, for communicating a PTC message to a PTC radio, a PTC controller can generally transmit a message to a common network address, without having to determine a specific network address for the PTC radio or otherwise.
If multiple vehicles each have on-board equipment with the same network address, however, and the network address cannot be changed because of system constraints (e.g., PTC standards), then connecting the vehicles in a local area network can cause addressing conflicts. This may result in poor network performance, system communication errors, control system errors (e.g., the wrong vehicle subsystems receiving and responding to the wrong messages), system inoperability, or the like.